Mercury is valuable to us because we can see the interactions between the planet and its space environment. This research aims to clarify how Mercury's neutral Na exosphere was produced. Data from MErcury Surface, Space ENvironment, GEochemistry, and Ranging/Mercury Atmospheric and Surface Composition Spectrometer (MESSENGER/MASCS) and model calculations that examine possible generation, transportation, and dissipation processes were compared. First, the seasonal variability in the amount of Na exosphere was analyzed for each local time (LT) using MASCS data. Previous research has shown that the amount of Na above LT12 reaches its maximum at the aphelion and that this maximum is recorded only at LT12. Following this result, we constructed a 3‐D Na exosphere model to understand the key seasonal variability processes occurring around LT12. The numerical calculation produced results that were consistent with the MASCS observations regarding the vertical profile and the seasonal variability at LT06 and LT18. However, the peak that occurs around the aphelion at LT12 could not be reproduced. However, the model produced results suggesting that less than 10⁸ kg of comet stream dust particles per Mercury year could be the local and short‐term source of Na.

中文翻译：

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MESSENGER数据和数值模拟推导的水银钠外层季节变化

汞对我们很有价值，因为我们可以看到地球与其空间环境之间的相互作用。这项研究旨在阐明水星的中性钠气圈是如何产生的。比较了水银表面，空间环境，地球化学和测距/水银大气和表面成分光谱仪（MESSENGER / MASCS）的数据以及检查可能的生成，运输和耗散过程的模型计算。首先，使用MASCS数据分析每个当地时间（LT）的纳克外层钠含量的季节性变化。先前的研究表明，LT12上方的Na的含量在a虫口达到其最大值，并且该最大值仅在LT12处记录。根据该结果，我们构建了一个3D Na外层大气模型，以了解LT12附近发生的关键季节性变化过程。数值计算得出的结果与MASCS关于LT06和LT18的垂直剖面和季节性变化的观测结果一致。但是，无法再现在LT12的顶峰周围出现的峰。但是，该模型产生的结果表明， 每年每汞10 ⁸ kg彗星流尘埃颗粒可能是本地和短期的Na来源。